η2-Alkynyl and Vinylidene Transition Metal Complexes. 7.1

Ikeda , Thomas P. Spaniol , Hayato Tsurugi , Kazushi Mashima , and Jun Okuda .... Atsunobu Terasoba , Suguru Matsuo , Maki Nakagawa , Hiroyuki Kaw...
0 downloads 0 Views 111KB Size
Download PDF
4840

Organometallics 2001, 20, 4840-4846

η2-Alkynyl and Vinylidene Transition Metal Complexes. 7.1 Hydroamination of Neutral Tungsten-Vinylidene Complexes Junes Ipaktschi,*,† Sascha Uhlig,† and Ansgar Du¨lmer‡ Institute of Organic Chemistry and Institute of Inorganic and Analytical Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany Received June 18, 2001

Primary and secondary amines 2a-d have been found to react in THF at room temperature with the vinylidene complexes [W(dCdCHR)(η5-C5H5)(CO)(NO)] (R ) C(CH3)3 (1), R ) Si(CH3)2C(CH3)3 (4)), affording the aminocarbene derivatives [W{dC(NR1R2)CH2C(CH3)3}(η5C5H5)(CO)(NO)] and [W{dC(NR1R2)CH2Si(CH3)2C(CH3)3}(η5-C5H5)(CO)(NO)] (R1 ) H, R2 ) n-C4H9 (3a, 5a); R1 ) H, R2 ) CH(CH3)2 (3b, 5b); R1 ) H, R2 ) C(CH3)3 (3c, 5c); R1 ) R2 ) (CH2)4 (3d, 5d)). At short reaction time the nucleophilic addition of both primary and secondary amines to 1 occurs at the carbonyl carbon atom, leading stereoselectively to the thermodynamically less stable η2-carbamoyl-(Z)-vinyl complexes [W{σ-(Z)-CHdCHC(CH3)3}{η2-C(O)NR1R2}(η5-C5H5)(NO)] (R1 ) H, R2 ) n-C4H9 (6a); R1 ) H, R2 ) CH(CH3)2 (6b); R1 ) H, R2 ) C(CH3)3 (6c); R1 ) R2 ) (CH2)4 (6d)). At higher amine concentration and prolonged reaction time 6a-d form the corresponding aminocarbene complexes 3a-d. The structure of 6b has been authenticated by a single-crystal X-ray diffraction analysis. Introduction Nucleophilic addition to unsaturated ligands such as alkynes, alkenes, and vinylidenes coordinated to a transition-metal center is involved as a key step in various stoichiometric and catalytic transformations mediated by organometallic species.2 Several examples of addition of nucleophiles, including water,3 alcohols,3a,e,g,4 and thiols,3e,5 as well as the addition of phosphines,6 to vinylidene complexes have been reported. In general the chemical reactivity of the vinylidene moiety is oriented †

Institute of Organic Chemistry. Institute of Inorganic and Analytical Chemistry. (1) Ipaktschi, J.; Klotzbach, T.; Du¨lmer, A. Organometallics 2000, 19, 5281-5286. (2) (a) Crabtree, R. H. The Organometallic Chemistry of the Transition Metals, 3rd ed.; Wiley-Interscience: New York, 2001. (b) Cornils, B.; Herrmann, W. Applied Homogeneous Catalysis with Organometallic Compounds (2 vols.); VCH: Oxford, U.K., 1996. (c) Collman, J. P.; Hegedus, L. S.; Norton, J. R.; Finke, R. G. Principles and Applications of Organotransition Metal Chemistry; University Science Books: Mill Valley, CA, 1987. (d) Yamamoto, A. Organotransition Metal Chemistry; Wiley-Interscience: New York, 1986. (e) Pearson, A. J. Metalloorganic Chemistry; Wiley-Interscience: New York, 1985. (3) (a) Bianchini, C.; Marchi, A.; Marvelli, L.; Peruzzini, M.; Romerosa, A.; Rossi, R. Organometallics 1996, 15, 3804-3816 and references therein. (b) Bianchini, C.; Casares, J. A.; Peruzzini, M.; Romerosa, A.; Zanobini, F. J. Am. Chem. Soc. 1996, 118, 4585-4594. (c) Knaup, W.; Werner, H. J. Organomet. Chem. 1991, 411, 471-489. (d) Mountassir, C.; Ben-Hadda, T.; Le Bozec, H. J. Organomet. Chem. 1990, 388, C13C16. (e) Boland-Lussier, B. E.; Hughes, R. P. Organometallics 1982, 1, 635-639. (f) Sullivan, B. P.; Smythe, R. S.; Kober, E. M.; Meyer, T. J. J. Am. Chem. Soc. 1982, 104, 4701-4703. (g) Bruce, M. I.; Swincer, A. G. Aust. J. Chem. 1980, 33, 1471-1483. (4) Bruce, M. I.; Swincer, A. G.; Wallis, R. C. J. Organomet. Chem. 1979, 171, C5-C8. (5) Bianchini, C.; Glendenning, L.; Peruzzini, M.; Romerosa, A.; Zanobini, F. J. Chem. Soc., Chem. Commun. 1994, 2219-2220. (6) (a) Bianchini, C.; Meli, A.; Peruzzini, M.; Zanobini, F.; Zanello, P. Organometallics 1990, 9, 241-250. (b) Senn, D. R.; Wong, A.; Patton, A. T.; Marsi, M.; Strouse, C. E.; Gladysz, J. A. J. Am. Chem. Soc. 1988, 110, 6096-6109. (c) Boland-Lussier, B. E.; Churchill, M. R.; Hughes, R. P.; Rheingold, A. L. Organometallics 1982, 1, 628-634. ‡

toward electrophilic attack at the β-carbon atom and nucleophilic attack at the R-carbon atom.7 Theoretical studies also predict the electron deficiency at the R-carbon and the localization of electron density in the MdC double bond and at the β-carbon.8,9 The additions of primary amines to cationic vinylidene complexes have been found to give aminocarbene derivatives.3e It is believed that this hydroamination reaction proceeds via a nucleophilic attack at the vinylidene R-carbon atom by the amine, followed by proton transfer (two steps), or as an intermolecularconcerted process (Scheme 1).10 Recently for a monosubstituted ruthenium vinylidene complex a mechanism involving 2 equiv of amine was postulated. In the first step of the reaction one molecule of amine deprotonates the vinylidene β-carbon atom, while a second one coordinates the metal center prior to a transfer onto the R-carbon atom of a σ-alkynyl intermediate.10 (7) (a) Del Rı´o, I.; van Koten, G. Tetrahedron Lett. 1999, 40, 14011404. (b) Buriez, B.; Cook, D. J.; Harlow, K. J.; Hill, A. F.; Welton, T.; White, A. J. P.; Williams, D. J.; Wilton-Ely, J. D. E. T. J. Organomet. Chem. 1999, 578, 264-267. (c) Wolf, J.; Stu¨er, W.; Gru¨nwald, C.; Werner, H.; Schwab, P.; Schulz, M. Angew. Chem. 1998, 110, 11651167. (d) Terry, M. R.; Mercando, L. A.; Kelley, C.; Geoffroy, G. L.; Nombel, P.; Lugan, N.; Mathieu, R.; Ostrander, R. L.; OwensWaltermire, B. E.; Rheingold, A. L. Organometallics 1994, 13, 843865. (8) Kostic, N. M.; Fenske, R. F. Organometallics 1982, 1, 974-982. (9) For general reviews see: (a) Puerta, M. C.; Valerga, P. Coord. Chem. Rev. 1999, 193-195, 977-1025. (b) Werner, H. Nachr. Chem., Tech. Lab. 1992, 40, 435-444. (c) Bruce, M. I. Chem. Rev. 1991, 91, 197-257. (d) Werner, H. Angew. Chem. 1990, 102, 1109-1121; Angew. Chem., Int. Ed. Engl. 1990, 29, 1077. (e) Davies, S. G.; McNally, J. P.; Smallridge, A. J. Adv. Organomet. Chem. 1990, 30, 1-76. (f) Antonova, A. B.; Johansson, A. A.; Russ. Chem. Rev. (Engl. Transl.) 1989, 58, 693-710. (g) Bruce, M. I.; Swincer, A. G. Adv. Organomet. Chem. 1983, 22, 59-128. (10) Bianchini, C.; Masi, D.; Romerosa, A.; Zanobini, F.; Peruzzini, M. Organometallics 1999, 18, 2376-2386.

10.1021/om010528s CCC: $20.00 © 2001 American Chemical Society Publication on Web 10/11/2001

η2-Alkynyl and Vinylidene Transition Metal Complexes Scheme 1

Organometallics, Vol. 20, No. 23, 2001 4841 Scheme 2

Intending to explore the reactivity of neutral tungsten vinylidene complexes, we investigated the reaction of monosubstituted vinylidene complexes 1 and 4 with a variety of amines. As a result, we have discovered an interesting pathway for the synthesis of complexes with a η2-carbamoyl group11 and a vinyl moiety.12 This paper describes the hydroamination of 1 and 4 to the aminocarbene derivatives 3a-d and 5a-d, the synthesis of the η2-carbamoyl-(Z)-vinyl complexes 6a-d, and the X-ray diffraction analysis of 6b. Results and Discussion Because of the presence of two electrophilic centers, CO and the vinylidene moiety, the tungsten vinylidene complex 1 shows a dichotomic behavior in reaction with amines. Treatment of 1 with a 20-fold excess of primary or secondary aliphatic amines 2a-d in THF at room temperature leads to the aminocarbenes 3a-d as a mixture of two rotamers by nucleophilic addition to the R-carbon atom of the vinylidene ligand (Scheme 2).13 Similarly, addition of 2a-d to a solution of 4 gives rise to the aminocarbenes 5a-d. The rates of the formation of the aminocarbenes appear to be dependent upon the steric properties of the amines. While the addition of amine 2a needs a few hours, the addition of 2c requires 2 days to be completed. In contrast to the aminocarbenes 5a,b,d, further purification was necessary for complexes 3a-d. Because of the sensitivity of these compounds to silica gel, which was used for chromatography, the yields are very low (around 30%). Compounds 3a and 5a-d are dark red viscous oils, and the remaining aminocarbenes are rosecolored (3b,d) or dark orange crystalline solids (3c) with good solubility in polar organic solvents. All aminocarbenes can be stored under an argon atmosphere at -20 °C for a few days. Their unequivocal characterization was achieved by means of standard spectroscopic tech(11) See, for example: (a) Anderson, S.; Cook, D. J.; Hill, A. F. Organometallics 1997, 16, 5595-5597. (b) Ishida, T.; Yasushi, M.; Tanase, T.; Hidai, M. J. Organomet. Chem. 1991, 409, 355-365. (c) Durfee, L. D.; Rothwell, I. P. Chem. Rev. 1988, 88, 1059-1079. (d) Fagan, P. J.; Manriquez, J. M.; Vollmer, S. H.; Day, C. S.; Day, V. W.; Marks, T. J. J. Am. Chem. Soc. 1981, 103, 2206-2220. (e) Mu¨ller, A.; Seyer, U.; Eltzner, W. Inorg. Chim. Acta 1979, 32, L65-66. (12) See, for example: (a) Paisner, S. N.; Burger, P.; Bergmann, R. G. Organometallics 2000, 19, 2073-2083. (b) Gamasa, M. P.; Gimeno, J.; Lastra, E.; Lanfranchi, M.; Tiripicchio, A. J. Organomet. Chem. 1992, 430, C39-C43. (c) Hoa Tran Huy, N.; Fischer, E. O.; Riede, J.; Thewalt, U.; Do¨tz, K. H. J. Organomet. Chem. 1984, 273, C29-C32. (d) Reger, D. L.; Belmore, K. A.; Mintz, E.; McElligott, P. J. Organometallics 1984, 3, 134-140. (e) Allen, S. R.; Baker, P. K.; Barnes, S. G.; Bottrill, M.; Green, M.; Orpen, A. G. J. Chem. Soc., Dalton Trans. 1983, 927-939. (f) Bruce, M. I.; Hambley, T. W.; Rodgers, J. R.; Snow, M. R.; Swincer, A. G. J. Organomet. Chem. 1982, 226, C1-C4. (g) Davison, A.; Selegue, J. P. J. Am. Chem. Soc. 1980, 102, 2455. (h) Davidson, J. L.; Shiralian, M. J. Chem. Soc., Chem. Commun. 1979, 30-32. (13) Aromatic amines such as aniline and tertiary amines such as dimethylethylamine do not react with 1 and 4.

Scheme 3

niques, particularly the 13C NMR signal at 252-262 ppm, characteristic for the R-carbon atom of the aminocarbenes, as well as elemental analyses, which were all consistent with the incorporation of one molecule of amine into the complex framework. Carbamoyl-Vinyl Complexes 6a-d. In a fast reaction, the nucleophilic addition of primary and secondary amines 2a-d to vinylidene complex 1 occurs first at the carbonyl carbon atom. Immediately after the color of the solution brightened up, the solvent and the excessive amine were removed under reduced pressure. The solid residue was dissolved in CH2Cl2, and addition of n-pentane gave beige (6a-c) or brown crystals (6d) of the η2-carbamoyl-(Z)-vinyl complexes of the general formula [W{σ-(Z)-CHdCHC(CH3)3}{η2-C(O)NR1R2}(η5C5H5)(NO)] (Scheme 3). The crystals of 6a-d can be stored without decomposition under an argon atmosphere at -20 °C for several months. The structure of the products were fully characterized by spetroscopic

4842

Organometallics, Vol. 20, No. 23, 2001

Ipaktschi et al. Table 1. Crystal Data and Conditions for Crystallographic Data Collection and Structure Refinement for 6b formula fw cryst size color cryst syst space group lattice constants

Figure 1. Molecular structure and atom-numbering scheme for [W{σ-(Z)-CHdCHC(CH3)3}{η2-C(O)NCH(CH3)2}(η5-C5H5)(NO)] (6b) with H atoms and thermal ellipsoids shown at the 30% probability level (ORTEP drawing).

methods, elemental analyses, and X-ray crystallographic studies of 6b. Spectroscopic Characterization. Significantly, the IR spectra of the carbamoyl-vinyl complexes exhibit a strong carbonyl band in the 1542-1551 cm-1 region. The substantially low C-O stretching frequency observed for 6a-d is consistent with the η2-coordination mode of the carbamoyl ligand.11b,d The nitrosyl group gives rise to a strong absorption in the range of 16261645 cm-1, and the medium IR band at 3190-3197 cm-1 can be assigned to the N-H stretching vibration of 6ac. The 1H and 13C NMR spectra show double sets of signals for 6a,b,d, because these complexes exist in solution as a mixture of rotational isomers. No conclusion can be made whether the rotational barrier around the W-C(alkenyl)12d or W-C(carbamoyl) bond11d,14 is responsible for the rotamers. The most notable feature in the 13C NMR spectra of the carbamoyl-vinyl complexes is a signal in the region of 200 ppm, which is assigned to the carbamoyl carbon atom. Complexes 6a-d show for the vinylic proton R to tungsten in the 1H NMR spectra a signal at 6.45-7.07 ppm and for the proton β to tungsten a signal in the range of 7.10-7.27 ppm. These signals appear with the corresponding satellite signals caused by the coupling with the 183W atom (14% 183W abundance; I ) 1/2): 2JH-W ≈ 12 Hz for HR and 3JH-W ≈ 9.5 Hz for Hβ. Because of the interaction of the tungsten atom with the vinyl π-system the 3JH-H coupling constant for the vinyl protons of ∼13.5 Hz is comparatively large for a Z-configured vinyl group. Molecular Structure of 6b. Suitable single crystals of [W{σ-(Z)-CHdCHC(CH3)3}{η2-C(O)NHCH(CH3)2}(η5C5H5)(NO)] (6b) were obtained upon slow diffusion of n-pentane into a solution of 6b in dichloromethane at -15 °C. The ORTEP drawing with atomic numbering scheme is provided in Figure 1, the crystallographic data are summarized in Table 1, and a list of selected bond distances and angles is given in Table 2. The geometry around the tungsten atom in 6b is a pseudo four-legged piano-stool configuration. The vinyl ligand σ-bonded to the tungsten atom forms one of the four legs of the pianoo stool and has a Z stereochemistry. The W-C(vinyl) bond length of 2.161(5) Å implies some π contribution to W-vinyl bonding via interaction of filled orbitals on the metal and the π* orbital of the vinyl ligand and (14) Erker, G.; Rosenfeldt, F. J. Organomet. Chem. 1980, 188, C1C4.

C15H24N2O2W 448.22 0.42 × 0.27 × 0.15 mm beige, transparent triclinic P1 h (No. 2) a ) 7.5194(8) Å b ) 10.5859(13) Å c ) 11.4778(15) Å R ) 91.200(15)° β ) 96.713(14)° γ ) 107.345(13)° vol 864.60(18) Å3 formula units per unit cell Z ) 2 density (calcd) 1.718 g cm-3 linear abs coeff 66.83 cm-1 diffractometer image plate diffractometer system (STOE) radiation Mo KR (λ ) 0.710 73 Å) monochromator graphite temp 293 K scan range 5.2° e 2θ e 56.1° -9 e h e 9, -13 e k e 13, -14 e l e 15 no. of rflns measd 7625 no. of indep rflns 3786 Rint 0.024 no. of indep rflns with 3239 Fo > 4σ(Fo) applied corrections Lorentz and polarizan coeffs structure determination W positional parameters from and refinement direct methods (program SHELXS-97a); further atoms from ∆F synthesis (program SHELXL97b), structure refinement by the anisotropic full-matrix least-squares procedure for all non-hydrogen atoms; hydrogen position refinement by “riding” model; atomic scattering factors from literaturec no. of params 181 wR2 0.0674 R1 0.0322 0.0247 R1 (Fo > 4σ(Fo)) max and min in ∆σ 1.079 and -1.154 e Å-3 a Sheldrick, G. M. SHELXS-97, Program for the Solution of Crystal Structures; Universita¨t Go¨ttingen, 1997. b Sheldrick, G. M. SHELXL-97, Program for Crystal Structure Refinement; Universita¨t Go¨ttingen, 1997. c International Tables for Crystallography; Wilson, A. J. C., Ed.; Kluwer Academic: Dordrecht, The Netherlands, 1992; Vol. C.

Table 2. Selected Bond Distances (Å) and Angles (deg) for 6b W-C(11) W-O(2) C(11)-O(2) C(11)-N(2) N(2)-C(12) W-C(21) N(1)-W-C(11) N(1)-W-C(21) C(11)-W-C(21) N(1)-W-O(2) C(11)-W-O(2) C(21)-W-O(2) O(1)-N(1)-W

Distances 2.036(5) C(21)-C(22) 2.202(4) C(22)-C(23) 1.273(6) range W1.305(6) C(Cp) 1.481(7) W-N(1) 2.161(5) N(1)-O(1)

1.332(8) 1.501(9) 2.287(6)2.402(5) 1.754(4) 1.232(5)

Angles 96.12(18) O(2)-C(11)-N(2) 97.90(18) O(2)-C(11)-W 115.2(2) N(2)-C(11)-W 102.00(17) C(11)-O(2)-W 34.67(16) C(11)-N(2)-C(12) 80.52(19) C(22)-C(21)-W 171.8(4) C(21)-C(22)-C(23)

126.6(5) 79.9(3) 153.5(4) 65.5(3) 124.1(4) 141.4(4) 133.1(5)

is shorter than the bond length in the tungsten vinyl complex such as [{WdC(OEt)(CHPh)2CdC(Me)CH(OEt)(NEt2)}(CO)4] (2.275(12) Å).12c The deviations of the W-CdC and CdC-C(CH3)3 angles (141.4(4) and 133.1-

η2-Alkynyl and Vinylidene Transition Metal Complexes Scheme 4

(5)°) from the ideal value 120° of a C(sp2) angle further reflects this interaction. The carbamoyl ligand is coordinated in η2 fashion and is coplanar with atoms W, C11, O2, N2, and C12 (dihedral angle W-O2-C11-N2 ) 178.9° and O2-C11-N2-C12 ) -3.2°) (Figure 1), indicating a stabilization of the arrangement due to an interaction of the π system with the metal. This is confirmed by the short W-C(carbamoyl) bond length of 2.036(5) Å. Mechanistic Considerations. Primarily, with a short reaction time, the nucleophilic attack of amines 2a-d occurs on the complex 1 at the carbonyl carbon atom to afford the η2-carbamoyl-(Z)-vinyl complexes 6ad. In the presence of an excess of the appropriate amine the complexes 6a-d are not stable and undergo an elimination reaction to generate the starting materials. With a longer reaction time the amine attacks again the complex 1 and leads via addition to the CR of the vinylidene moiety to the aminocarbenes 3a-d (Scheme 3). Experimental evidence of this mechanism was provided by the following observation: in the presence of aniline or dimethylethylamine, which are unreactive toward vinylidene 1, the complexes 6a-d are not stable and create an equilibrium mixture of vinylidene 1 and the corresponding η2-carbamoyl-vinyl complex as well as the aminocarbene derivative.15 Treating 6a with dimethylethylamine generates a mixture of 6a, 1, and aminocarbene 3a in a ratio of 2:2:1 after 6 h. After longer reaction time the concentration of 6a and 1 diminish and the amount of 3a increases. We suggest that the initial formation of the thermodynamically less stable Z isomers of the η2-carbamoyl-vinyl complexes 6a-d proceeds in two steps (Scheme 4). First the addition of amines 2a-d to the carbonyl group of 1 generates the anion 7, which is protonated by an (15) Also, 1H NMR spectroscopy shows the presence of a small amount of vinylidene 1, and some decomposed products which could not be identified, when a solution of the η2-carbamoyl-vinyl complex 6a in CDCl3 was allowed to stand for several hours at room temperature.

Organometallics, Vol. 20, No. 23, 2001 4843

ammonium ion anti to the tert-butyl group due to the bulky size of this substituent. The outcome of the reaction is the formation of a vinyl moiety, which resembles formally an addition of hydride to the CR atom of the vinylidene group.12b,g Monitoring the reaction of vinylidene 4 and n-butylamine by 1H NMR spectroscopy in THF-d8 did not show any carbamoyl derivatives along with the formation of the aminocarbene 5a. Obviously in the case of complex 4, amine attack occurs only at the vinylidene CR atom, because a negative charge at the position β to the tungsten atom can be stabilized by the R effect of the silyl group.16 Concluding Remarks. It is shown that the outcome of the additions depends on the vinylidene precursor leading stereoselectively to η2-carbamoyl-(Z)-vinyl complexes in a short reaction time when a tert-butylsubstituted vinylidene complex is used as a precursor. These results show a novel reactivity pattern in the nucleophilic addition of amines to vinylidene complexes bearing carbonyl ligands as competitive electrophilic sites. We believe that the η2-carbamoyl-vinyl complexes are not intermediates in the pathway to the appropriate aminocarbenes because the η2-carbamoyl-vinyl complexes form an equilibrium mixture with the starting materials in the presence of an excess of amine. Experimental Section General Considerations. All reactions were carried out under an argon atmosphere (99.99%, by Messer-Griesheim) with the use of standard Schlenk techniques. Solvents were purified by standard methods and distilled under argon prior to use. Literature methods were used to prepare [W(η5-C5H5)(CO)2(NO)],17 (tert-butyldimethylsilyl)acetylene,18 and [W {dCdCHC(CH3)2}(η5-C5H5)(CO)(NO)] (4).19 Amines were purchased from Fluka, their purity was checked by 1H NMR spectroscopy, and, when necessary, they were dried over KOH and distilled from CaH2 under an argon atmosphere prior to use. All other compounds were commercially available. NMR spectra were obtained on Bruker AM 400 and AC 200 spectrometers. Proton and carbon chemical shifts are reported in ppm relative to the residual proton resonance (7.24 ppm) or the carbon multiplet (77.0 ppm) of the NMR solvent CDCl3. 13C-DEPT, 1H,13C-2D correlation, and 1H,13C-2D COLOC NMR experiments were run on the Bruker AM 400 spectrometer. MS measurements (70 eV) were performed on a Varian MAT 311-A. IR spectra were recorded on a Bruker FT-IR IFS 85. Microanalyses were done on a Carlo Erba 1104 elemental analyzer. Preparation of Compounds. [W{dCdCHSi(CH3)2C(CH3)3}(η5-C5H5)(CO)(NO)] (4). At -78 °C 3 mL (4.5 mmol) of n-BuLi (a solution of 1.5 mmol/mL in hexane) was added to a solution of 0.63 g (4.5 mmol) of (tert-butyldimethylsilyl)acetylene in 10 mL of THF. This soltution was added to 1.0 g (3.0 mmol) of [W(η5-C5H5)(CO)2(NO)] in 60 mL of THF, whereby the color changed from orange to deep green. Addition of 1 mL of concentrated HCl diluted with 20 mL of water led to a dark red solution. After the reaction mixture was allowed to reach room temperature, the THF was removed under reduced pressure. The residue was extracted with diethyl ether, washed with saturated aqueous sodium chloride, and (16) Reissig, H. U. Chem. Unserer Zeit 1984, 18, 46-53. (17) Chin, T. T.; Hoyano, J. K.; Legzdins, P.; Malito, J. T. Inorg. Synth. 1990, 28, 196-198. (18) Holmes, A. B.; Sporikou, C. N. Organic Syntheses; Wiley: New York, 1983; Collect. Vol. VIII, pp 606-609. (19) Ipaktschi, J.; Demuth-Eberle, G. J.; Mirzaei, F.; Mu¨ller, B. G.; Beck, J.; Serafin, M. Organometallics 1995, 14, 3335-3341.

4844

Organometallics, Vol. 20, No. 23, 2001

dried over magnesium sulfate. Chromatography of the dark red oil on silica gel with 3:1 n-pentane/diethyl ether yielded 0.85 g (63%) of 4 as orange crystals, mp 62 °C. Anal. Calcd for C14H21NO2SiW: C, 37.60; H, 4,73, N, 3.13. Found: C, 37.49; H, 4.38; N, 3.29. Two rotamers were found in the NMR spectra. 1 H NMR (CDCl3, 400.13 MHz): δ 5.75 (s, 5H, Cp), 5.70 and 5.66 (2 s, 2:3, 1H, CβH), 0.92 and 0.89 [2 s, 3:2, 9H, Si(CH3)2C(CH3)3], 0.14 and 0.10 [2 s, 2:3, 6H, Si(CH3)2C(CH3)3]. 13C NMR (CDCl3, 100.61 MHz): δ 332.7 and 330.7 (2 CR), 213.9 and 213.0 (2 CO), 118.7 and 117.7 (2 Cβ), 95.4 and 95.3 (2 Cp), 26.2 [2 Si(CH3)2C(CH3)3], 17.6 and 17.2 [Si(CH3)2C(CH3)3], -4.5 and -4.7 [2 Si(CH3)2C(CH3)3]. IR (KBr; ν˜ (cm-1)): 1992 (s, Cd O), 1653 (s, NtO), 1601 (s, CdC). MS (70 eV): m/e 447 (M+, 184W), 419 (M+ - CO). High-resolution mass spectrum: m/e calcd for C14H21NO2Si182W (M+) 445.0825, found 445.0806. Synthesis of the Aminocarbene Complexes [W{dC(NR1R2)CH2C(CH3)3}(η5-C5H5)(CO)(NO)] (R1 ) H, R2 ) n-C4H9 (3a); R1 ) H, R2 ) CH(CH3)3 (3b); R1 ) H, R2 ) C(CH3)3 (3c); R1 ) R2 ) (CH2)4 (3d)). General Procedure. A 20-fold excess of the appropriate primary amine (NH2R; R ) n-C4H9, CH(CH3)3, C(CH3)3) or secondary amine (pyrrolidine) was syringed at room temperature into a stirred red solution of the vinylidene complex 1 (0.50 g, 1.29 mmol) in 25 mL of THF. The color of the reaction mixture brightened and was dark red in the end. When the reaction was complete, the volatile components were removed under reduced pressure. After evaporation to dryness under vacuum the residue was chromatographed on silica gel with 1:1 n-pentane/diethyl ether. In the case of a solid residue the product was recrystallized additionally from CH2Cl2 and n-pentane. [W{dC(NH-n-C4H9)CH2C(CH3)3}(η5-C5H5)(CO)(NO)] (3a): reaction time 7 h, dark red viscous oil (210 mg, 35%). Anal. Calcd for C16H26N2O2W: C, 41.57; H, 5.67, N, 6.06. Found: C, 41.44; H, 5.56; N, 5.83. Two rotamers were found in the NMR spectra. 1H NMR (CDCl3, 400.13 MHz): δ 7.31 (br s, 1H, NH), 5.54 (2JH-W ) 8.9 Hz) and 5.52 (2 s, 15:1, 5H, Cp), 3.52-3.40 and 3.23-3.18 (2 m, 15:1, 2H, CH2CH2CH2CH3), 2.92 (2JH-H ) 12.8 Hz), 2.86 (12.3 Hz), 2.61 (12.3 Hz) and 2.40 (12.8 Hz) (4 d, AB system, 1:15:1:15, 2H, CH2C(CH3)3), 1.70-1.62 (m, 2H, CH2CH2CH2CH3), 1.47-1.37 (m, 2H, CH2CH2CH2CH3), 1.17 (3JH-H ) 7.1 Hz) and 0.94 (7.4 Hz) (2 t, 1:15, 3H, CH2CH2CH2CH3), 1.00 and 0.95 [2 s, 1:15, 9H, C(CH3)3]. 13C NMR (CDCl3, 100.61 MHz): δ 262.0 (1JC-W ) 159.5 Hz) (carbene C), 232.0 (CO), 93.9 and 93.8 (Cp), 66.5 [CH2C(CH3)3], 52.5 (CH2CH2CH2CH3), 33.0 [C(CH3)3], 31.4 (CH2CH2CH2CH3), 31.0 and 29.8 [C(CH3)3], 20.4 (CH2CH2CH2CH3), 13.7 (CH2CH2CH2CH3). IR (KBr; ν˜ (cm-1)): 3265 (w, N-H), 1905 (s, CdO), 1559 (s, NtO). MS (70 eV): m/e 462 (M+, 184W), 434 (M+ - CO). High-resolution mass spectrum: m/e calcd for C16H26N2O2182W (M+) 460.1477, found 460.1453. [W{dC(NHCH(CH3)2)CH2C(CH3)3}(η5-C5H5)(CO)(NO)] (3b): reaction time 15 h, rose-colored crystals (223 mg, 39%; mp 143 °C). Anal. Calcd for C15H24N2O2W: C, 40.20; H, 5.40, N, 6.25. Found: C, 40.61; H, 5.27; N, 6.24. Two rotamers were found in the NMR spectra. 1H NMR (CDCl3, 400.13 MHz): δ 7.23 (br s, 1H, NH), 5.55 and 5.51 (2 s, 22:1, 5H, Cp), 4.134.04 [m, 1H, CH(CH3)2], 2.75 (2JH-H ) 12.8 Hz) and 2.34 (12.8 Hz) [2 d, AB system 2H, CH2C(CH3)3], 1.30 (3JH-H ) 2.0 Hz) and 1.28 (3JH-H ) 2.0 Hz) [2 d, diastereotopic methyl groups, 6H, CH(CH3)2], 1.01 and 0.95 [2 s, 1:22, 9H, C(CH3)3]. 13C NMR (CDCl3, 100.61 MHz): δ 258.7 (1JC-W ) 159.5 Hz) (carbeneC), 232.7 (CO), 93.8 (Cp), 66.4 [CH2C(CH3)3], 53.4 [CH(CH3)2], 33.1 [C(CH3)3], 31.1 [C(CH3)3], 22.8 and 22.7 [CH(CH3)2]. IR (KBr; ν˜ (cm-1)): 3267 (m, N-H), 1898 (s, CdO), 1570 (s, Nt O). MS (70 eV): m/e 448 (M+, 184W), 420 (M+ - CO). Highresolution mass spectrum: m/e calcd for C15H24N2O2182W (M+) 446.1321, found 446.1348. [W{dC(NHC(CH3)3)CH2C(CH3)3}(η5-C5H5)(CO)(NO)] (3c): reaction time 43 h, dark orange crystals (169 mg, 28%; mp 108 °C). Anal. Calcd for C16H26N2O2W: C, 41.57; H, 5.67, N, 6.06. Found: C, 41.45; H, 5.68; N, 5.84. 1H NMR (CDCl3,

Ipaktschi et al. 400.13 MHz): δ 7.70 (br s, 1H, NH), 5.59 (2JH-W ) 9.1 Hz) (s, 5H, Cp), 2.49 (2JH-H ) 13.3 Hz) and 2.23 (13.3) [2 d, AB system, 2H, CH2C(CH3)3], 1.58 [s, 9H, NHC(CH3)3], 0.95 [s, 9H, C(CH3)3]. 13C NMR (CDCl3, 50.32 MHz): δ 258.9 (carbene C), 231.7 (CO), 94.4 (Cp), 67.5 (CH2C(CH3)3), 56.2 [NHC(CH3)3], 33.5 [C(CH3)3], 31.3 [NHC(CH3)3], 28.9 [C(CH3)3]. IR (KBr; ν˜ (cm-1)): 3278 (m, N-H), 1897 (s, CdO), 1559 (s, NtO). MS (70 eV): m/e 462 (M+, 184W), 434 (M+ - CO). High-resolution mass spectrum: m/e calcd for C16H26N2O2182W (M+) 460.1477, found 460.1512. [W{dC(cyclo-NC4H8)CH2C(CH3)3}(η5-C5H5)(CO)(NO)] (3d): reaction time 7 h, rose-colored crystals (184 mg, 31%; mp 177 °C). Anal. Calcd for C16H24N2O2W: C, 41.76; H, 5.26, N, 6.09. Found: C, 41.52; H, 4.97; N, 6.21. 1H NMR (CDCl3, 400.13 MHz): δ 5.50 (2JH-W ) 8.9 Hz) (s, 5H, Cp), 3.72-3.59 and 3.39 (m and br s, 4H, CH2CH2CH2CH2), 2.96 (2JH-H ) 10.1 Hz) [br d, 2H, CH2C(CH3)3], 2.02-1.91 (m, 4H, CH2CH2CH2CH2), 1.01 [s, 9H, C(CH3)3]. 13C NMR (CDCl3, 100.61 MHz): δ 258.3 (carbene C), 236.1 (CO), 93.9 (Cp), 61.2 and 60.7 [CH2C(CH3)3], 52.1 and 45.2 (CH2CH2CH2CH2), 33.5 [C(CH3)3], 31.3 [C(CH3)3], 25.6 and 25.0 (CH2CH2CH2CH2). IR (KBr; ν˜ (cm-1)): 1878 (s, CdO), 1574 (s, NtO). MS (70 eV): m/e 460 (M+, 184 W), 430 (M+ - NO). High-resolution mass spectrum: m/e calcd for C16H24N2O2182W (M+) 458.1321, found 458.1354. Synthesis of the Aminocarbene Complexes [W{dC(NR1R2)CH2Si(CH3)2C(CH3)3}(η5-C5H5)(CO)(NO)] (R1 ) H, R2 ) n-C4H9 (5a); R1 ) H, R2 ) CH(CH3)2 (5b); R1 ) H, R2 ) C(CH3)3 (5c); R1 ) R2 ) (CH2)4 (5d)). General Procedure. A 20-fold excess of the appropriate primary amine (NH2R; R ) n-C4H9, CH(CH3)2, C(CH3)3) or secondary amine (pyrrolidine) was syringed at room temperature into a stirred solution of the vinylidene complex 4 (0.50 g, 1.29 mmol) in 25 mL of THF. The color of the reaction mixture changed from orange to red. When the reaction was complete, the volatile components were removed under reduced pressure and dried under vacuum. The samples were spetroscopically pure, and no effort was made for any further purification. [W{dC(NH-n-C4H9)CH2Si(CH3)2C(CH3)3}(η5-C5H5)(CO)(NO)] (5a): reaction time 1 h, dark red viscous oil (quantitative yield). Anal. Calcd for C18H32N2O2SiW: C, 41.54; H, 6.20, N, 5.38. Found: C, 41.64; H, 6.59; N, 5.70. Two rotamers were found in the NMR spectra. 1H NMR (CDCl3, 400.13 MHz): δ 7.81 and 6.98 (2 br s, 2:3, 1H, NH), 5.55 (2JH-W ) 8.9 Hz) and 5.51 (8.9 Hz) (2 s, 3:2, 5H, Cp), 3.58-3.42, 3.37-3.28, and 3.17-3.09 [4 m (partly overlapping), diastereotopic protons, 2H, CH2CH2CH2CH3], 2.85 (2JH-H ) 10.9 Hz), 2.59 (12.0 Hz), 2.46 (10.9 Hz), and 2.42 (12.1 Hz) [4 d, AB system, 2:3:2:3, 2H, CH2Si(CH3)2C(CH3)3], 1.70-1.60 (m, 2H, CH2CH2CH2CH3), 1.48-1.36 (m, 2H, CH2CH2CH2CH3), 0.96 (3JH-H ) 7.3 Hz) and 0.95 (7.3 Hz) (2 t, 3:2, 3H, CH2CH2CH2CH3), 0.90 and 0.87 [2 s, 2:3, 9H, Si(CH3)2C(CH3)3], 0.11 (2JH-Si ) 5.9 Hz), 0.07, 0.06, and 0.01 (2JH-Si ) 5.9 Hz) [4 s, diastereotopic methyl groups, 2:3:2:3, 6H, Si(CH3)2C(CH3)3]. 13C NMR (CDCl3, 100.61 MHz): δ 259.7 and 259.3 (carbene C), 236.5 and 233.0 (CO), 93.7 and 93.6 (Cp), 52.3 and 46.8 (CH2CH2CH2CH3), 43.3 and 37.8 [CH2Si(CH3)2C(CH3)3], 31.7 and 31.4 (CH2CH2CH2CH3), 26.3 [Si(CH3)2C(CH3)3], 20.4 and 20.1 (CH2CH2CH2CH3), 17.5 and 17.0 [Si(CH3)2C(CH3)3], 13.8 and 13.7 (CH2CH2CH2CH3), -4.1, -4.7, -5.5 and -6.1 [Si(CH3)2C(CH3)3]. IR (KBr; ν˜ (cm-1)): 3260 (w, N-H), 1901 (s, CdO), 1559 (s, NtO). MS (70 eV): m/e 520 (M+, 184W), 492 (M+ - CO). High-resolution mass spectrum: m/e calcd for C18H32N2O2Si182W (M+) 518.1716, found 518.1713. [W{dC(NHCH(CH3)2)CH2Si(CH3)2C(CH3)3}(η5-C5H5)(CO)(NO)] (5b): reaction time 3 h, dark red viscous oil (quantitative yield). Anal. Calcd for C17H30N2O2SiW: C, 40.32; H, 5.97, N, 5.53. Found: C, 40.09; H, 5.89; N, 5.37. Two rotamers were found in the NMR spectra. 1H NMR (CDCl3, 400.13 MHz): δ 7.63 and 6.88 (2 br s, 1:3, 1H, NH), 5.54 (2JH-W ) 9.5 Hz) and 5.50 (8.8 Hz) (2 s, 3:1, 5H, Cp), 4.17-4.08 and 3.75-3.66 [2 m, 3:1, 1H, CH(CH3)2], 2.86 (2JH-H ) 11.0 Hz), 2.52 (11.0 Hz)

η2-Alkynyl and Vinylidene Transition Metal Complexes and 2.46 (12.1 Hz), 2.42 (12.1 Hz) [4 d, AB system, 1:1:3:3, 2H, CH2Si(CH3)2C(CH3)3], 1.29 (3JH-H ) 5.5 Hz), 1.28 (5.5 Hz) and 1.24 (6.6 Hz), 1.20 (6.3 Hz) [4 d, diastereotopic methyl groups, 3:3:1:1, 6H, CH(CH3)2], 0.89 and 0.86 [2 s, 1:3, 9H, Si(CH3)2C(CH3)3], 0.10, 0.08 (2JH-Si ) 6.6 Hz), 0.04 and 0.01 (2JH-Si ) 6.6 Hz) [4 s, diastereotopic methyl groups, 1:3:1:3, 6H, Si(CH3)2C(CH3)3]. 13C NMR (CDCl3, 100.61 MHz): δ 257.7 and 255.9 (carbene C), 236.7 and 233.8 (CO), 93.7 and 93.6 (Cp), 53.2 and 48.1 [CH(CH3)2], 43.1 and 37.1 [CH2Si(CH3)2C(CH3)3], 26.3 and 26.3 [Si(CH3)2C(CH3)3], 23.4 and 23.1 [CH(CH3)2], 22.8 and 22.4 [CH(CH3)2], 17.3 and 16.9 [Si(CH3)2C(CH3)3], -4.2, -4.6, -5.5, and -6.4 [Si(CH3)2C(CH3)3]. IR (KBr; ν˜ (cm-1)): 3252 (m, N-H), 1895 (s, CdO), 1558 (s, NtO). MS (70 eV): m/e 506 (M+, 184W), 476 (M+ - NO). Highresolution mass spectrum: m/e calcd for C17H30N2O2Si182W (M+) 504.1559, found 504.1557. [W{dC(NHC(CH3)3)CH2Si(CH3)2C(CH3)3}(η5-C5H5)(CO)(NO)] (5c): reaction time 43 h. Additional chromatography of the residue on silica gel with 3:1 n-pentane/diethyl ether was necessary to yield 138 mg (69%) of 5c as a dark red viscous oil and 7% of vinylidene complex 4. Anal. Calcd for C18H32N2O2SiW: C, 41.54; H, 6.20, N, 5.38. Found: C, 41.06; H, 6.22; N, 5.14. Two rotamers were found in the NMR spectra. 1H NMR (CDCl3, 400.13 MHz): δ 8.01 and 7.39 (2 br s, 1:8, 1H, NH), 5.57 (2JH-W ) 8.9 Hz) and 5.47 (8.9 Hz) (2 s, 8:1, 5H, Cp), 3.31 (2JH-H ) 11.3 Hz), 2.59 (10.8), 2.23 (12.8) and 2.18 (12.8) [4 d, AB system, 1:1:8:8, 2H, CH2Si(CH3)2C(CH3)3], 1.50 and 1.43 [2 s, 8:1, 9H, NHC(CH3)3], 0.89 and 0.84 [2 s, 1:8, 9H, Si(CH3)2C(CH3)3], 0.12, 0.08 [2JH-Si ) 5.9 Hz] and 0.03 [3 s, diastereotopic methyl groups, 6H, Si(CH3)2C(CH3)3]. 13C NMR (CDCl3, 100.61 MHz): δ 256.3 [1J(183W,13C) ) 152.2 Hz] (carbene C), 233.2 (CO), 94.2 and 93.7 (Cp), 57.7 and 56.0 [NHC(CH3)3], 44.4 and 38.8 [CH2Si(CH3)2C(CH3)3], 31.2 and 29.1 [NHC(CH3)3], 26.9 and 26.2 [Si(CH3)2C(CH3)3], 16.9 [Si(CH3)2C(CH3)3], -3.3, -4.5, -5.2, and -5.6 [Si(CH3)2C(CH3)3]. IR (KBr; ν˜ (cm-1)): 3326 (w, N-H), 1901 (s, CdO), 1570 (s, NtO). MS (70 eV): m/e 520 (M+, 184W), 492 (M+ - CO), 462 (M+ - CO - NO). High-resolution mass spectrum: m/e calcd for C18H32N2O2Si182W (M+) 518.1716, found 518.1683. [W{dC(cyclo-NC4H8)CH2Si(CH3)2C(CH3)3}(η5-C5H5)(CO)(NO)] (5d): reaction time 1 h, dark red viscous oil (quantitative yield). Anal. Calcd for C18H30N2O2SiW: C, 41.71; H, 5.83, N, 5.40. Found: C, 41.21; H, 5.80; N, 5.22. 1H NMR (CDCl3, 400.13 MHz): δ 5.49 (2JH-W ) 8.9 Hz) (s, 5H, Cp), 3.77, 3.603.53, and 3.48-3.41 (br s and 2 m, 4H, CH2CH2CH2CH2), 2.78 (2JH-H ) 10.8 Hz) and 2.69 [br d and br s, AB system, 2H, CH2Si(CH3)2C(CH3)3], 2.10-1.90 (m, 4H, CH2CH2CH2CH2), 0.89 [s, 9H, Si(CH3)2C(CH3)3], 0.12 and 0.04 [2 s, diastereotopic methyl groups, 6H, Si(CH3)2C(CH3)3]. 13C NMR (CDCl3, 100.61 MHz): δ 252.4 (1JC-W ) 158.1 Hz) (carbene C), 237.1 (CO), 93.7 (Cp), 60.3 and 51.8 (CH2CH2CH2CH2), 40.8 [CH2Si(CH3)2C(CH3)3], 26.4 [Si(CH3)2C(CH3)3], 25.9 and 25.3 (CH2CH2CH2CH2), 17.6 [Si(CH3)2C(CH3)3], -3.9 and -6.2 [Si(CH3)2C(CH3)3]. IR (KBr; ν˜ (cm-1)): 1889 (s, CdO), 1576 (s, NtO). MS (70 eV) m/e 518 (M+, 184W), 488 (M+ - NO). Highresolution mass spectrum: m/e calcd for C18H30N2O2Si182W (M+) 516.1559, found 516.1554. Synthesis of the η2-Carbamoyl-(Z)-Vinyl Complexes [W{σ-(Z)-CHdCHC(CH 3 ) 3 }{η 2 -C(O)NR 1 R 2 }(η 5 -C 5 H 5 )(NO)] (R1 ) H, R2 ) n-C4H9 (6a); R1 ) H, R2 ) CH(CH3)2 (6b); R1 ) H, R2 ) C(CH3)3 (6c); R1 ) R2 ) (CH2)4 (6d)). General Procedure. A 20-fold excess of the appropriate primary amine (NH2R; R ) n-C4H9, CH(CH3)2, C(CH3)3) or secondary amine (pyrrolidine) was syringed at room temperature into a stirred red solution of the vinylidene complex 1 (0.20 g, 0.51 mmol) in 10 mL of THF. The reaction was stopped immediately when the color of the reaction mixture changed to yellow (6a) or brightened up (6b-d) by rapid removal of the volatile components under reduced pressure. After evaporation to dryness under vacuum the solid residue was dissolved in 1-2 mL of CH2Cl2. The solution was cooled to -78 °C.

Organometallics, Vol. 20, No. 23, 2001 4845 Addition of ca. 10 mL of n-pentane gave beige crystals of the carbamoyl-vinyl complex, which were collected on sinteredglass frits and washed with n-pentane (2 × 5 mL) before being dried under vacuum. [W{σ-(Z)-CHdCHC(CH3)3}{η2-C(O)NH-n-C4H9}(η5-C5H5)(NO)] (6a): reaction time about 1 min, beige crystals (186 mg, 78%; mp 95-97 °C dec). Anal. Calcd for C16H26N2O2W: C, 41.57; H, 5.67, N, 6.06. Found: C, 41.61; H, 5.79; N, 6.01. Two rotamers were found in the NMR spectra. 1H NMR (CDCl3, 400.13 MHz): δ 9.06 (3JH-H ) 4.8 Hz) (br t, 1H, NH), 7.27 (3JH-W ) 9.6 Hz, 3JH-H ) 13.6 Hz) and 7.25 (3JH-H ) 13.2 Hz) [2 d, 11:1, 1H, WCHdCHC(CH3)3], 7.07 (2JH-W ) 12.1 Hz, 3J 3 H-H ) 13.6 Hz) and 7.03 ( JH-H ) 13.6 Hz) [2 d, 1:11, 1H, WCHdCHC(CH3)3], 5.84 and 5.82 (2JH-W ) 9.2 Hz) (2 s, 1:11, 5H, Cp), 3.58-3.56 and 3.52 (3JH-H ) 6.7 Hz) (m and dq, 1:11, 2H, CH2CH2CH2CH3), 1.70-1.63 and 1.60-1.52 (2 m, 1:11, 2H, CH2CH2CH2CH3), 1.47-1.39 and 1.39-1.30 (2 m, 1:11, 2H, CH2CH2CH2CH3), 1.19 and 1.17 [2 s, 11:1, 9H, C(CH3)3], 0.96 (3JH-H ) 7.5 Hz) and 0.91 (7.4 Hz) (2 t, 1:11, 3H, CH2CH2CH2CH3). 13C NMR (CDCl3, 100.61 MHz): δ 212.1 (CO), 158.4 [WCHdCHC(CH3)3], 148.6 (1JC-W ) 110.6 Hz) [WCHdCHC(CH3)3], 100.7 and 100.2 (Cp), 44.7 (CH2CH2CH2CH3), 35.3 [C(CH3)3], 31.5 (CH2CH2CH2CH3), 30.8 [C(CH3)3], 20.0 (CH2CH2CH2CH3), 13.8 (CH2CH2CH2CH3). IR (KBr; ν˜ (cm-1)): 3190 (m, N-H), 1645 (s, NtO), 1544 (m, CdO). MS (70 eV): m/e 434 (M+ - CO, 184W). High-resolution mass spectrum: m/e calcd for C16H26N2O2182W (M+) 432.1528 (-CO), found 432.1541. [W{σ-(Z)-CHdCHC(CH3)3}{η2-C(O)NHCH(CH3)2}(η5C5H5)(NO)] (6b): reaction time about 5 min, beige crystals (193 mg, 84%; mp 110-112 °C dec). Anal. Calcd for C15H24N2O2W: C, 40.20; H, 5.40, N, 6.25. Found: C, 40.08; H, 5.18; N, 6.34. Two rotamers were found in the NMR spectra. 1H NMR (CDCl , 400.13 MHz): δ 8.89 (3J 3 H-H ) 7.4 Hz) (br d, 1H, NH), 7.27 (3JH-W ) 9.4 Hz, 3JH-H ) 13.8 Hz) [d, 1H, WCHd CHC(CH3)3], 7.05 (2JH-W ) 11.8 Hz, 3JH-H ) 13.3 Hz) [d, 1H, WCHdCHC(CH3)3], 5.84 and 5.82 (2JH-W ) 9.2 Hz) (2 s, 1:20, 5H, Cp), 4.25-4.17 (3JH-H ) 6.9 Hz) [sextet, 1H, CH(CH3)2], 1.40, 1.27, 1.26, and 1.23 [4 d, 1:1:20:20, 2H, CH(CH3)2], 1.20 and 1.16 [2 s, 20:1, 9H, C(CH3)3]. 13C NMR (CDCl3, 100.61 MHz): δ 212.4 (CO), 158.2 [WCHdCHC(CH3)3], 149.1 (1JC-W ) 114.4 Hz) [WCHdCHC(CH3)3], 100.8 and 100.1 (Cp), 47.8 [CH(CH3)2], 35.5 [C(CH3)3], 31.1 [C(CH3)3], 22.8 [CH(CH3)2]. IR (KBr; ν˜ (cm-1)): 3197 (m, N-H), 1627 (s, NtO), 1551 (s, CdO). MS (70 eV): m/e 420 (M+ - CO, 184W). High-resolution mass spectrum: m/e calcd for C15H24N2O2182W (M+) 418.1371 (-CO), found 418.1380. [W{σ-(Z)-CHdCHC(CH3)3}{η2-C(O)NHC(CH3)3}(η5-C5H5)(NO)] (6c): reaction time about 5 min, beige crystals (43 mg, 18%; mp 125-127 °C dec). Anal. Calcd for C16H26N2O2W: C, 41.57; H, 5.67, N, 6.06. Found: C, 41.45; H, 5.68; N, 5.84. 1H NMR (CDCl3, 400.13 MHz): δ 9.52 (br s, 1H, NH), 7.27 (3JH-W ) 10.3 Hz, 3JH-H ) 13.6 Hz) [d, 1H, WCHdCHC(CH3)3], 7.06 (2JH-W ) 11.8 Hz, 3JH-H ) 13.6 Hz) [d, 1H, WCHdCHC(CH3)3], 5.82 (2JH-W ) 9.2 Hz) (s, 5H, Cp), 1.44 [s, 9H, NHC(CH3)3], 1.19 [s, 9H, WCHdCHC(CH3)3]. 13C NMR (CDCl3, 100.61 MHz): δ 211.9 (CO), 158.6 [WCHdCHC(CH3)3], 147.8 [WCHd CHC(CH3)3], 100.7 (Cp), 56.2 [NHC(CH3)3], 35.6 [WCHd CHC(CH3)3], 30.8 [NHC(CH3)3], 28.8 [WCHdCHC(CH3)3]. IR (KBr; ν˜ (cm-1)): 3190 (m, N-H), 1626 (s, NtO), 1542 (s, Cd O). MS (70 eV): m/e 434 (M+ - CO, 184W). High-resolution mass spectrum: m/e calcd for C16H26N2O2182W (M+) 432.1528 (-CO), found 432.1503. [W{σ-(Z)-CHdCHC(CH3)3}{η2-C(O)-cyclo-NC4H8}(η5C5H5)(NO)] (6d): reaction time about 15 min, brown crystals (100 mg, 42%; mp 89-91 °C dec). Anal. Calcd for C16H24N2O2W: C, 41.76; H, 5.26, N, 6.09. Found: C, 41.20; H, 5.04; N, 6.15. Two rotamers were found in the NMR spectra. 1H NMR (CDCl , 400.13 MHz): δ 7.25 (3J 3 3 H-W ) 9.6 Hz, JH-H ) 13.3 Hz) and 7.10 (3JH-H ) 12.8 Hz) [2 d, 6:1, 1H, WCHd CHC(CH3)3], 7.06 (2JH-W ) 12.3 Hz, 3JH-H ) 13.3 Hz) and 6.45 (3JH-H ) 13.3 Hz) [2 d, 6:1, 1H, WCHdCHC(CH3)3], 5.90 and

4846

Organometallics, Vol. 20, No. 23, 2001

5.81 (2JH-W ) 9.4 Hz) (2 s, 1:6, 5H, Cp), 4.37, 4.00-3.94, 3.793.72, 3.67-3.61, and 3.26 (5 m, 4H, CH2CH2CH2CH2), 2.121.98, 1.86, and 1.76-1.71 (3 m, 4H, CH2CH2CH2CH2), 1.15 and 1.07 [2 s, 6:1, 9H, C(CH3)3]. 13C NMR (CDCl3, 100.61 MHz): δ 213.0 and 184.2 (CO), 159.3 and 158.2 [WCHdCHC(CH3)3], 151.4 (1JC-W ) 150.0 Hz) and 148.8 (111.9 Hz) [WCHdCHC(CH3)3], 102.8 and 99.8 (Cp), 67.1, 64.5, 49.7, and 48.5 (CH2CH2CH2CH2), 35.5 and 35.2 [C(CH3)3], 31.1 and 30.8 [C(CH3)3], 26.7, 26.5, and 25.1 (CH2CH2CH2CH2). IR (KBr; ν˜ (cm-1)): 1635 (s, NtO), 1546 (s, CdO). MS (70 eV): m/e 432 (M+ CO, 184W). High-resolution mass spectrum: m/e calcd for C16H24N2O2182W (M+) 430.1371 (-CO), found 430.1359.

Ipaktschi et al.

Acknowledgment. This work was supported by the Deutsche Forschungsgemeinschaft. Supporting Information Available: Listings giving data for the crystal structure determination and refinement, atomic coordinates, interatomic distances and angles, anisotropic thermal parameters, and hydrogen parameters of the compound 6b. This material is available free of charge via the Internet at http://pubs.acs.org. OM010528S